fiv/fiv.c

//
// fiv.c: fuck-if-I-know-how-to-name-it image browser and viewer
//
// Copyright (c) 2021 - 2022, Přemysl Eric Janouch <p@janouch.name>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
//

#include <glib.h>
#include <glib/gstdio.h>
#include <gtk/gtk.h>

#include <errno.h>
#include <math.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>

#include "config.h"

#include "fiv-browser.h"
#include "fiv-io.h"
#include "fiv-sidebar.h"
#include "fiv-thumbnail.h"
#include "fiv-view.h"

// --- Utilities ---------------------------------------------------------------

static void exit_fatal(const gchar *format, ...) G_GNUC_PRINTF(1, 2);

static void
exit_fatal(const gchar *format, ...)
{
	va_list ap;
	va_start(ap, format);

	gchar *format_nl = g_strdup_printf("%s\n", format);
	vfprintf(stderr, format_nl, ap);
	free(format_nl);

	va_end(ap);
	exit(EXIT_FAILURE);
}

// --- Keyboard shortcuts ------------------------------------------------------
// Fuck XML, this can be easily represented in static structures.
// Though it would be nice if the accelerators could be customized.

struct key {
	const char *accelerator;
	const char *title;
};

struct key_group {
	const char *title;
	const struct key *keys;
};

struct key_section {
	const char *title;
	const char *section_name;
	const struct key_group *groups;
};

static struct key help_keys_general[] = {
	{"F1 <control>F1", "Show this list of shortcuts"},
	{"F11 f", "Toggle fullscreen view"},
	{"<alt><shift>d", "Toggle dark theme variant"},
	{"q <control>q", "Exit the program"},
	{"Escape <control>w", "Exit the program"},
	{}
};

static struct key_group help_keys_browser[] = {
	{"General", help_keys_general},
	{"View", (struct key[]) {
		{"F9", "Toggle navigation sidebar"},
		{}
	}},
	{"Navigation", (struct key[]) {
		{"<control>l", "Open location..."},
		{"<control>n", "Open a new window"},
		{"<alt>Left", "Go back in history"},
		{"<alt>Right", "Go forward in history"},
		{"<alt>Up", "Go to parent directory"},
		{"<alt>Home", "Go home"},
		{"F5 r <control>r", "Refresh"},
		{}
	}},
	{}
};

static struct key_group help_keys_view[] = {
	{"General", help_keys_general},
	{"View", (struct key[]) {
		{"F8", "Toggle toolbar"},
		{}
	}},
	{"Navigation", (struct key[]) {
		{"<control>l", "Open location..."},
		{"<control>n", "Open a new window"},
		{"Left Up Page_Up", "Previous image"},
		{"Right Down Page_Down", "Next image"},
		{"Return <alt>Left", "Return to browser"},
		{}
	}},
	{"Zoom", (struct key[]) {
		{"<control>0", "Set zoom to 100%"},
		{"1...9", "Set zoom to N:1"},
		{"plus <control>plus", "Zoom in"},
		{"minus <control>minus", "Zoom out"},
		{"w", "Zoom to fit width if larger"},
		{"h", "Zoom to fit height if larger"},
		{}
	}},
	{"Orientation", (struct key[]) {
		{"less", "Rotate anticlockwise"},
		{"equal", "Mirror"},
		{"greater", "Rotate clockwise"},
		{}
	}},
	{"Configuration", (struct key[]) {
#ifdef HAVE_LCMS2
		{"c", "Toggle color management"},
#endif
		{"x", "Toggle scale to fit if larger"},
		{"i", "Toggle smooth scaling"},
		{"t", "Toggle transparency highlighting"},
#ifdef HAVE_JPEG_QS
		{"e", "Toggle low-quality JPEG enhancement"},
#endif
		{}
	}},
	{"Control", (struct key[]) {
		{"bracketleft", "Previous page"},
		{"bracketright", "Next page"},
		{"braceleft", "Previous frame"},
		{"braceright", "Next frame"},
		{"space", "Toggle playback"},
		{}
	}},
	{"Tools", (struct key[]) {
		{"<control>p", "Print..."},
		{"<control>s", "Save page as..."},
		{"<control><shift>s", "Save frame as..."},
		{"<alt>Return", "Show file information"},
		{}
	}},
	{}
};

static struct key_section help_keys[] = {
	{"Browser", "browser", help_keys_browser},
	{"View", "view", help_keys_view},
	{}
};

static GtkWidget *
make_key(const struct key *key)
{
	return gtk_widget_new(GTK_TYPE_SHORTCUTS_SHORTCUT,
		"title", key->title,
		"shortcut-type", GTK_SHORTCUT_ACCELERATOR,
		"accelerator", key->accelerator, NULL);
}

static GtkWidget *
make_key_group(const struct key_group *group)
{
	GtkWidget *widget = gtk_widget_new(
		GTK_TYPE_SHORTCUTS_GROUP, "title", group->title, NULL);
	for (const struct key *p = group->keys; p->title; p++)
		gtk_container_add(GTK_CONTAINER(widget), make_key(p));
	return widget;
}

static GtkWidget *
make_key_section(const struct key_section *section)
{
	GtkWidget *widget = gtk_widget_new(GTK_TYPE_SHORTCUTS_SECTION,
		"title", section->title, "section-name", section->section_name, NULL);
	for (const struct key_group *p = section->groups; p->title; p++)
		gtk_container_add(GTK_CONTAINER(widget), make_key_group(p));
	return widget;
}

static GtkWidget *
make_key_window(void)
{
	GtkWidget *window = gtk_widget_new(GTK_TYPE_SHORTCUTS_WINDOW, NULL);
	for (const struct key_section *p = help_keys; p->title; p++) {
		GtkWidget *section = make_key_section(p);
		gtk_widget_show_all(section);
		gtk_container_add(GTK_CONTAINER(window), section);
	}
	return window;
}

// --- Main --------------------------------------------------------------------

// TODO(p): See if it's possible to give separators room to shrink
// by some minor amount of pixels, margin-wise.
#define B make_toolbar_button
#define T make_toolbar_toggle
#define TOOLBAR(XX) \
	XX(BROWSE,        B("view-grid-symbolic", "Browse")) \
	XX(FILE_PREVIOUS, B("go-previous-symbolic", "Previous file")) \
	XX(FILE_NEXT,     B("go-next-symbolic", "Next file")) \
	XX(S1,            gtk_separator_new(GTK_ORIENTATION_HORIZONTAL)) \
	XX(PAGE_FIRST,    B("go-top-symbolic", "First page")) \
	XX(PAGE_PREVIOUS, B("go-up-symbolic", "Previous page")) \
	XX(PAGE_NEXT,     B("go-down-symbolic", "Next page")) \
	XX(PAGE_LAST,     B("go-bottom-symbolic", "Last page")) \
	XX(S2,            gtk_separator_new(GTK_ORIENTATION_HORIZONTAL)) \
	XX(SKIP_BACK,     B("media-skip-backward-symbolic", "Rewind playback")) \
	XX(SEEK_BACK,     B("media-seek-backward-symbolic", "Previous frame")) \
	XX(PLAY_PAUSE,    B("media-playback-start-symbolic", "Pause")) \
	XX(SEEK_FORWARD,  B("media-seek-forward-symbolic", "Next frame")) \
	XX(S3,            gtk_separator_new(GTK_ORIENTATION_HORIZONTAL)) \
	XX(PLUS,          B("zoom-in-symbolic", "Zoom in")) \
	XX(SCALE,         gtk_label_new("")) \
	XX(MINUS,         B("zoom-out-symbolic", "Zoom out")) \
	XX(ONE,           B("zoom-original-symbolic", "Original size")) \
	XX(FIT,           T("zoom-fit-best-symbolic", "Scale to fit")) \
	XX(S4,            gtk_separator_new(GTK_ORIENTATION_HORIZONTAL)) \
	/* XX(PIN,        B("view-pin-symbolic", "Keep view configuration")) */ \
	/* Or perhaps "blur-symbolic", also in the extended set. */ \
	XX(COLOR,         T("preferences-color-symbolic", "Color management")) \
	XX(SMOOTH,        T("blend-tool-symbolic", "Smooth scaling")) \
	XX(CHECKERBOARD,  T("checkerboard-symbolic", "Highlight transparency")) \
	XX(ENHANCE,       T("heal-symbolic", "Enhance low-quality JPEG")) \
	XX(S5,            gtk_separator_new(GTK_ORIENTATION_HORIZONTAL)) \
	XX(SAVE,          B("document-save-as-symbolic", "Save as...")) \
	XX(PRINT,         B("document-print-symbolic", "Print...")) \
	XX(INFO,          B("info-symbolic", "Information")) \
	XX(S6,            gtk_separator_new(GTK_ORIENTATION_HORIZONTAL)) \
	XX(LEFT,          B("object-rotate-left-symbolic", "Rotate left")) \
	XX(MIRROR,        B("object-flip-horizontal-symbolic", "Mirror")) \
	XX(RIGHT,         B("object-rotate-right-symbolic", "Rotate right")) \
	XX(S7,            gtk_separator_new(GTK_ORIENTATION_HORIZONTAL)) \
	/* We are YouTube. */ \
	XX(FULLSCREEN,    B("view-fullscreen-symbolic", "Fullscreen"))

enum {
#define XX(id, constructor) TOOLBAR_ ## id,
	TOOLBAR(XX)
#undef XX
	TOOLBAR_COUNT
};

struct {
	FivIoModel *model;         ///< "directory" contents
	gchar *directory;          ///< URI of the currently browsed directory
	GList *directory_back;     ///< History paths as URIs going backwards
	GList *directory_forward;  ///< History paths as URIs going forwards
	GPtrArray *files;          ///< "directory" contents as URIs

	gchar *uri;                ///< Current image URI, if any
	gint files_index;          ///< Where "uri" is within "files"

	GtkWidget *window;
	GtkWidget *stack;

	GtkWidget *browser_paned;
	GtkWidget *browser_sidebar;
	GtkWidget *plus;
	GtkWidget *minus;
	GtkWidget *sort_field[FIV_IO_MODEL_SORT_COUNT];
	GtkWidget *sort_direction[2];
	GtkWidget *browser_scroller;
	GtkWidget *browser;

	GtkWidget *view_box;
	GtkWidget *view_toolbar;
	GtkWidget *toolbar[TOOLBAR_COUNT];
	GtkWidget *view;
} g;

static void
show_error_dialog(GError *error)
{
	GtkWidget *dialog =
		gtk_message_dialog_new(GTK_WINDOW(g.window), GTK_DIALOG_MODAL,
			GTK_MESSAGE_ERROR, GTK_BUTTONS_CLOSE, "%s", error->message);
	gtk_dialog_run(GTK_DIALOG(dialog));
	gtk_widget_destroy(dialog);
	g_error_free(error);
}

static void
set_window_title(const char *uri)
{
	GFile *file = g_file_new_for_uri(uri);
	gchar *name = g_file_get_parse_name(file);
	gtk_window_set_title(GTK_WINDOW(g.window), name);
	g_free(name);
	g_object_unref(file);
}

static void
switch_to_browser(void)
{
	set_window_title(g.directory);
	gtk_stack_set_visible_child(GTK_STACK(g.stack), g.browser_paned);
	gtk_widget_grab_focus(g.browser_scroller);
}

static void
switch_to_view(void)
{
	g_return_if_fail(g.uri != NULL);

	set_window_title(g.uri);
	gtk_stack_set_visible_child(GTK_STACK(g.stack), g.view_box);
	gtk_widget_grab_focus(g.view);
}

static gchar *
parent_uri(GFile *child_file)
{
	GFile *parent = g_file_get_parent(child_file);
	gchar *parent_uri = g_file_get_uri(parent);
	g_object_unref(parent);
	return parent_uri;
}

static void
update_files_index(void)
{
	g.files_index = -1;
	for (guint i = 0; i < g.files->len; i++)
		if (!g_strcmp0(g.uri, g_ptr_array_index(g.files, i)))
			g.files_index = i;
}

static void
load_directory_without_reload(const gchar *uri)
{
	gchar *uri_duplicated = g_strdup(uri);
	if (g.directory_back && !strcmp(uri, g.directory_back->data)) {
		// We're going back in history.
		if (g.directory) {
			g.directory_forward =
				g_list_prepend(g.directory_forward, g.directory);
			g.directory = NULL;
		}

		GList *link = g.directory_back;
		g.directory_back = g_list_remove_link(g.directory_back, link);
		g_list_free_full(link, g_free);
	} else if (g.directory_forward && !strcmp(uri, g.directory_forward->data)) {
		// We're going forward in history.
		if (g.directory) {
			g.directory_back =
				g_list_prepend(g.directory_back, g.directory);
			g.directory = NULL;
		}

		GList *link = g.directory_forward;
		g.directory_forward = g_list_remove_link(g.directory_forward, link);
		g_list_free_full(link, g_free);
	} else if (g.directory && strcmp(uri, g.directory)) {
		// We're on a new subpath.
		g_list_free_full(g.directory_forward, g_free);
		g.directory_forward = NULL;

		g.directory_back = g_list_prepend(g.directory_back, g.directory);
		g.directory = NULL;
	}

	g_free(g.directory);
	g.directory = uri_duplicated;
}

static void
load_directory_without_switching(const gchar *uri)
{
	if (uri) {
		load_directory_without_reload(uri);

		GtkAdjustment *vadjustment = gtk_scrolled_window_get_vadjustment(
			GTK_SCROLLED_WINDOW(g.browser_scroller));
		gtk_adjustment_set_value(
			vadjustment, gtk_adjustment_get_lower(vadjustment));
	}

	g_ptr_array_set_size(g.files, 0);
	g.files_index = -1;

	GError *error = NULL;
	GFile *file = g_file_new_for_uri(g.directory);
	if (fiv_io_model_open(g.model, file, &error)) {
		g_ptr_array_free(g.files, TRUE);
		g.files = fiv_io_model_get_files(g.model);
		update_files_index();
	} else if (g_error_matches(error, G_IO_ERROR, G_IO_ERROR_NOT_SUPPORTED)) {
		g_error_free(error);
	} else {
		show_error_dialog(error);
	}

	g_object_unref(file);

	gtk_widget_set_sensitive(
		g.toolbar[TOOLBAR_FILE_PREVIOUS], g.files->len > 1);
	gtk_widget_set_sensitive(
		g.toolbar[TOOLBAR_FILE_NEXT], g.files->len > 1);
}

static void
load_directory(const gchar *uri)
{
	load_directory_without_switching(uri);

	// XXX: When something outside the filtered entries is open, the index is
	// kept at -1, and browsing doesn't work. How to behave here?
	// Should we add it to the pointer array as an exception?
	if (uri) {
		switch_to_browser();

		// TODO(p): Rather place it in history.
		g_clear_pointer(&g.uri, g_free);
	}
}

static void
on_filtering_toggled(GtkToggleButton *button, G_GNUC_UNUSED gpointer user_data)
{
	g_object_set(
		g.model, "filtering", gtk_toggle_button_get_active(button), NULL);
}

static void
on_sort_field(G_GNUC_UNUSED GtkMenuItem *item, gpointer data)
{
	g_object_set(g.model, "sort-field", (gint) (intptr_t) data, NULL);
}

static void
on_sort_direction(G_GNUC_UNUSED GtkMenuItem *item, gpointer data)
{
	g_object_set(g.model, "sort-descending", (gboolean) (intptr_t) data, NULL);
}

static void
open(const gchar *uri)
{
	GFile *file = g_file_new_for_uri(uri);

	GError *error = NULL;
	if (!fiv_view_open(FIV_VIEW(g.view), uri, &error)) {
		const char *path = g_file_peek_path(file);
		// TODO(p): Use g_file_info_get_display_name().
		gchar *base = g_filename_display_basename(path ? path : uri);
		g_object_unref(file);

		g_prefix_error(&error, "%s: ", base);
		show_error_dialog(error);
		g_free(base);
		return;
	}

	gtk_recent_manager_add_item(gtk_recent_manager_get_default(), uri);
	g_list_free_full(g.directory_forward, g_free);
	g.directory_forward = NULL;

	g_free(g.uri);
	g.uri = g_strdup(uri);

	// So that load_directory() itself can be used for reloading.
	gchar *parent = parent_uri(file);
	if (!g.files->len /* hack to always load the directory after launch */ ||
		!g.directory || strcmp(parent, g.directory))
		load_directory_without_switching(parent);
	else
		update_files_index();
	g_free(parent);

	switch_to_view();
}

static GtkWidget *
create_open_dialog(void)
{
	GtkWidget *dialog = gtk_file_chooser_dialog_new("Open file",
		GTK_WINDOW(g.window), GTK_FILE_CHOOSER_ACTION_OPEN,
		"_Cancel", GTK_RESPONSE_CANCEL,
		"_Open", GTK_RESPONSE_ACCEPT, NULL);
	gtk_file_chooser_set_local_only(GTK_FILE_CHOOSER(dialog), FALSE);

	GtkFileFilter *filter = gtk_file_filter_new();
	for (const char **p = fiv_io_supported_media_types; *p; p++)
		gtk_file_filter_add_mime_type(filter, *p);
#ifdef HAVE_GDKPIXBUF
	gtk_file_filter_add_pixbuf_formats(filter);
#endif  // HAVE_GDKPIXBUF
	gtk_file_filter_set_name(filter, "Supported images");
	gtk_file_chooser_add_filter(GTK_FILE_CHOOSER(dialog), filter);

	GtkFileFilter *all_files = gtk_file_filter_new();
	gtk_file_filter_set_name(all_files, "All files");
	gtk_file_filter_add_pattern(all_files, "*");
	gtk_file_chooser_add_filter(GTK_FILE_CHOOSER(dialog), all_files);
	return dialog;
}

static void
on_open(void)
{
	static GtkWidget *dialog;
	if (!dialog)
		dialog = create_open_dialog();

	// Apparently, just keeping the dialog around doesn't mean
	// that it will remember its last location.
	(void) gtk_file_chooser_set_current_folder_uri(
		GTK_FILE_CHOOSER(dialog), g.directory);

	// The default is local-only, single item.
	switch (gtk_dialog_run(GTK_DIALOG(dialog))) {
		gchar *uri;
	case GTK_RESPONSE_ACCEPT:
		uri = gtk_file_chooser_get_uri(GTK_FILE_CHOOSER(dialog));
		open(uri);
		g_free(uri);
		break;
	case GTK_RESPONSE_NONE:
		dialog = NULL;
		return;
	}

	gtk_widget_hide(dialog);
}

static void
on_previous(void)
{
	if (g.files_index >= 0) {
		int previous = (g.files->len + g.files_index - 1) % g.files->len;
		open(g_ptr_array_index(g.files, previous));
	}
}

static void
on_next(void)
{
	if (g.files_index >= 0) {
		int next = (g.files_index + 1) % g.files->len;
		open(g_ptr_array_index(g.files, next));
	}
}

static void
spawn_uri(const char *uri)
{
	char *argv[] = {PROJECT_NAME, (char *) uri, NULL};
	GError *error = NULL;
	g_spawn_async(
		NULL, argv, NULL, G_SPAWN_SEARCH_PATH, NULL, NULL, NULL, &error);
	g_clear_error(&error);
}

static void
on_item_activated(G_GNUC_UNUSED FivBrowser *browser, GFile *location,
	GtkPlacesOpenFlags flags, G_GNUC_UNUSED gpointer data)
{
	gchar *uri = g_file_get_uri(location);
	if (flags == GTK_PLACES_OPEN_NEW_WINDOW)
		spawn_uri(uri);
	else
		open(uri);
	g_free(uri);
}

static void open_any_file(GFile *file, gboolean force_browser);

static void
on_mounted_enclosing(GObject *source_object, GAsyncResult *res,
	G_GNUC_UNUSED gpointer user_data)
{
	GFile *file = G_FILE(source_object);
	GError *error = NULL;
	if (!g_file_mount_enclosing_volume_finish(file, res, &error))
		show_error_dialog(error);
	else
		open_any_file(file, FALSE);
}

static void
open_any_file(GFile *file, gboolean force_browser)
{
	GFileType type = g_file_query_file_type(file, G_FILE_QUERY_INFO_NONE, NULL);
	if (type == G_FILE_TYPE_UNKNOWN &&
		G_FILE_GET_IFACE(file)->mount_enclosing_volume) {
		// TODO(p): At least provide some kind of indication.
		GMountOperation *op = gtk_mount_operation_new(GTK_WINDOW(g.window));
		g_file_mount_enclosing_volume(file, G_MOUNT_MOUNT_NONE, op, NULL,
			on_mounted_enclosing, NULL);
		g_object_unref(op);
		return;
	}

	gchar *uri = g_file_get_uri(file);
	if (type == G_FILE_TYPE_UNKNOWN) {
		errno = ENOENT;
		show_error_dialog(g_error_new(G_FILE_ERROR,
			g_file_error_from_errno(errno), "%s: %s", uri, g_strerror(errno)));
	} else if (type == G_FILE_TYPE_DIRECTORY) {
		load_directory(uri);
	} else if (force_browser) {
		// GNOME, e.g., invokes this as a hint to focus the particular file,
		// which we can't currently do yet.
		gchar *parent = parent_uri(file);
		load_directory(parent);
		g_free(parent);
	} else {
		open(uri);
	}
	g_free(uri);
}

static void
on_open_location(G_GNUC_UNUSED GtkPlacesSidebar *sidebar, GFile *location,
	GtkPlacesOpenFlags flags, G_GNUC_UNUSED gpointer user_data)
{
	gchar *uri = g_file_get_uri(location);
	if (flags & GTK_PLACES_OPEN_NEW_WINDOW)
		spawn_uri(uri);
	else
		open_any_file(location, FALSE);
	g_free(uri);
}

static void
on_toolbar_zoom(G_GNUC_UNUSED GtkButton *button, gpointer user_data)
{
	FivThumbnailSize size = FIV_THUMBNAIL_SIZE_COUNT;
	g_object_get(g.browser, "thumbnail-size", &size, NULL);

	size += (gintptr) user_data;
	g_return_if_fail(size >= FIV_THUMBNAIL_SIZE_MIN &&
		size <= FIV_THUMBNAIL_SIZE_MAX);

	g_object_set(g.browser, "thumbnail-size", size, NULL);
}

static void
on_notify_thumbnail_size(
	GObject *object, GParamSpec *param_spec, G_GNUC_UNUSED gpointer user_data)
{
	FivThumbnailSize size = 0;
	g_object_get(object, g_param_spec_get_name(param_spec), &size, NULL);
	gtk_widget_set_sensitive(g.plus, size < FIV_THUMBNAIL_SIZE_MAX);
	gtk_widget_set_sensitive(g.minus, size > FIV_THUMBNAIL_SIZE_MIN);
}

static void
on_notify_filtering(
	GObject *object, GParamSpec *param_spec, gpointer user_data)
{
	gboolean b = FALSE;
	g_object_get(object, g_param_spec_get_name(param_spec), &b, NULL);
	gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(user_data), b);
}

static void
on_notify_sort_field(
	GObject *object, GParamSpec *param_spec, G_GNUC_UNUSED gpointer user_data)
{
	gint field = -1;
	g_object_get(object, g_param_spec_get_name(param_spec), &field, NULL);
	gtk_check_menu_item_set_active(
		GTK_CHECK_MENU_ITEM(g.sort_field[field]), TRUE);
}

static void
on_notify_sort_descending(
	GObject *object, GParamSpec *param_spec, G_GNUC_UNUSED gpointer user_data)
{
	gboolean b = FALSE;
	g_object_get(object, g_param_spec_get_name(param_spec), &b, NULL);
	gtk_check_menu_item_set_active(
		GTK_CHECK_MENU_ITEM(g.sort_direction[b]), TRUE);
}

static void
toggle_fullscreen(void)
{
	if (gdk_window_get_state(gtk_widget_get_window(g.window)) &
		GDK_WINDOW_STATE_FULLSCREEN)
		gtk_window_unfullscreen(GTK_WINDOW(g.window));
	else
		gtk_window_fullscreen(GTK_WINDOW(g.window));
}

static void
on_window_state_event(G_GNUC_UNUSED GtkWidget *widget,
	GdkEventWindowState *event, G_GNUC_UNUSED gpointer user_data)
{
	if (!(event->changed_mask & GDK_WINDOW_STATE_FULLSCREEN))
		return;

	const char *name = (event->new_window_state & GDK_WINDOW_STATE_FULLSCREEN)
		? "view-restore-symbolic"
		: "view-fullscreen-symbolic";

	GtkButton *button = GTK_BUTTON(g.toolbar[TOOLBAR_FULLSCREEN]);
	GtkImage *image = GTK_IMAGE(gtk_button_get_image(button));
	gtk_image_set_from_icon_name(image, name, GTK_ICON_SIZE_BUTTON);
}

static void
on_help_destroyed(GtkWidget *window, GtkWidget **storage)
{
	g_return_if_fail(*storage == window);
	*storage = NULL;
}

static void
show_help_shortcuts(void)
{
	static GtkWidget *window;
	if (!window) {
		window = make_key_window();
		g_signal_connect(
			window, "destroy", G_CALLBACK(on_help_destroyed), &window);
	}

	g_object_set(window, "section-name",
		gtk_stack_get_visible_child(GTK_STACK(g.stack)) == g.view_box
			? "view"
			: "browser",
		NULL);
	gtk_widget_show(window);
}

// Cursor keys, e.g., simply cannot be bound through accelerators
// (and GtkWidget::keynav-failed would arguably be an awful solution).
//
// GtkBindingSets can be added directly through GtkStyleContext,
// but that would still require setting up action signals on the widget class,
// which is extremely cumbersome.  GtkWidget::move-focus has no return value,
// so we can't override that and abort further handling.
//
// Therefore, bind directly to keypresses.  Order can be fine-tuned with
// g_signal_connect{,after}(), or overriding the handler and either tactically
// chaining up or using gtk_window_propagate_key_event().
static gboolean
on_key_press(G_GNUC_UNUSED GtkWidget *widget, GdkEventKey *event,
	G_GNUC_UNUSED gpointer data)
{
	switch (event->state & gtk_accelerator_get_default_mod_mask()) {
	case GDK_MOD1_MASK | GDK_SHIFT_MASK:
		if (event->keyval == GDK_KEY_D) {
			GtkSettings *settings = gtk_settings_get_default();
			const char *property = "gtk-application-prefer-dark-theme";
			gboolean set = FALSE;
			g_object_get(settings, property, &set, NULL);
			g_object_set(settings, property, !set, NULL);
		}
		break;
	case GDK_CONTROL_MASK:
		switch (event->keyval) {
		case GDK_KEY_o:
			on_open();
			return TRUE;
		case GDK_KEY_l:
			fiv_sidebar_show_enter_location(FIV_SIDEBAR(g.browser_sidebar));
			return TRUE;
		case GDK_KEY_n:
			spawn_uri(g.directory);
			return TRUE;
		case GDK_KEY_r:
			// TODO(p): Reload the image instead, if it's currently visible.
			load_directory(NULL);
			return TRUE;
		case GDK_KEY_q:
		case GDK_KEY_w:
			gtk_widget_destroy(g.window);
			return TRUE;

		case GDK_KEY_F1:
			show_help_shortcuts();
			return TRUE;
		}
		break;
	case GDK_MOD1_MASK:
		switch (event->keyval) {
		case GDK_KEY_Left:
			if (gtk_stack_get_visible_child(GTK_STACK(g.stack)) == g.view_box)
				switch_to_browser();
			else if (g.directory_back)
				load_directory(g.directory_back->data);
			return TRUE;
		case GDK_KEY_Right:
			if (g.directory_forward)
				load_directory(g.directory_forward->data);
			else if (g.uri)
				switch_to_view();
			return TRUE;
		case GDK_KEY_Up:
			if (gtk_stack_get_visible_child(GTK_STACK(g.stack)) != g.view_box) {
				GFile *directory = g_file_new_for_uri(g.directory);
				gchar *parent = parent_uri(directory);
				g_object_unref(directory);
				load_directory(parent);
				g_free(parent);
			}
			return TRUE;
		case GDK_KEY_Home:
			if (gtk_stack_get_visible_child(GTK_STACK(g.stack)) != g.view_box) {
				gchar *uri = g_filename_to_uri(g_get_home_dir(), NULL, NULL);
				load_directory(uri);
				g_free(uri);
			}
			return TRUE;
		}
		break;
	case 0:
		switch (event->keyval) {
		case GDK_KEY_Escape:
		case GDK_KEY_q:
			gtk_widget_destroy(g.window);
			return TRUE;

		case GDK_KEY_o:
			on_open();
			return TRUE;
		case GDK_KEY_F5:
		case GDK_KEY_r:
			// TODO(p): See the comment for C-r above.
			load_directory(NULL);
			return TRUE;

		case GDK_KEY_F1:
			show_help_shortcuts();
			return TRUE;
		case GDK_KEY_F9:
			gtk_widget_set_visible(g.browser_sidebar,
				!gtk_widget_is_visible(g.browser_sidebar));
			return TRUE;

		case GDK_KEY_F11:
		case GDK_KEY_f:
			toggle_fullscreen();
			return TRUE;
		}
	}
	return FALSE;
}

static gboolean
on_key_press_view(G_GNUC_UNUSED GtkWidget *widget, GdkEventKey *event,
	G_GNUC_UNUSED gpointer data)
{
	switch (event->state & gtk_accelerator_get_default_mod_mask()) {
	case 0:
		switch (event->keyval) {
		case GDK_KEY_F8:
			gtk_widget_set_visible(g.view_toolbar,
				!gtk_widget_is_visible(g.view_toolbar));
			return TRUE;

		case GDK_KEY_Left:
		case GDK_KEY_Up:
		case GDK_KEY_Page_Up:
			on_previous();
			return TRUE;

		case GDK_KEY_Right:
		case GDK_KEY_Down:
		case GDK_KEY_Page_Down:
			on_next();
			return TRUE;

		case GDK_KEY_Return:
			switch_to_browser();
			return TRUE;
		}
		break;
	}
	return FALSE;
}

static gboolean
on_button_press_view(G_GNUC_UNUSED GtkWidget *widget, GdkEventButton *event)
{
	if ((event->state & gtk_accelerator_get_default_mod_mask()))
		return FALSE;
	switch (event->button) {
	case 8:  // back
		switch_to_browser();
		return TRUE;
	case GDK_BUTTON_PRIMARY:
		if (event->type == GDK_2BUTTON_PRESS) {
			toggle_fullscreen();
			return TRUE;
		}
		return FALSE;
	default:
		return FALSE;
	}
}

static gboolean
on_button_press_browser_paned(
	G_GNUC_UNUSED GtkWidget *widget, GdkEventButton *event)
{
	if ((event->state & gtk_accelerator_get_default_mod_mask()))
		return FALSE;
	switch (event->button) {
	case 8:  // back
		if (g.directory_back)
			load_directory(g.directory_back->data);
		return TRUE;
	case 9:  // forward
		if (g.directory_forward)
			load_directory(g.directory_forward->data);
		else if (g.uri)
			switch_to_view();
		return TRUE;
	default:
		return FALSE;
	}
}

static GtkWidget *
make_toolbar_button(const gchar *symbolic, const gchar *tooltip)
{
	GtkWidget *button =
		gtk_button_new_from_icon_name(symbolic, GTK_ICON_SIZE_BUTTON);
	gtk_widget_set_tooltip_text(button, tooltip);
	gtk_widget_set_focus_on_click(button, FALSE);
	gtk_style_context_add_class(
		gtk_widget_get_style_context(button), GTK_STYLE_CLASS_FLAT);
	return button;
}

static GtkWidget *
make_toolbar_toggle(const gchar *symbolic, const gchar *tooltip)
{
	GtkWidget *button = gtk_toggle_button_new();
	gtk_button_set_image(GTK_BUTTON(button),
		gtk_image_new_from_icon_name(symbolic, GTK_ICON_SIZE_BUTTON));
	gtk_widget_set_tooltip_text(button, tooltip);
	gtk_widget_set_focus_on_click(button, FALSE);
	gtk_style_context_add_class(
		gtk_widget_get_style_context(button), GTK_STYLE_CLASS_FLAT);
	return button;
}

static void
on_view_actions_changed(void)
{
	gboolean has_image = FALSE, can_animate = FALSE;
	gboolean has_previous = FALSE, has_next = FALSE;
	g_object_get(g.view, "has-image", &has_image, "can-animate", &can_animate,
		"has-previous-page", &has_previous, "has-next-page", &has_next, NULL);

	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_PAGE_FIRST], has_previous);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_PAGE_PREVIOUS], has_previous);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_PAGE_NEXT], has_next);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_PAGE_LAST], has_next);

	// We don't want these to flash during playback.
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_SKIP_BACK], can_animate);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_SEEK_BACK], can_animate);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_PLAY_PAUSE], can_animate);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_SEEK_FORWARD], can_animate);

	// Note that none of the following should be visible with no image.
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_PLUS], has_image);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_SCALE], has_image);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_MINUS], has_image);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_ONE], has_image);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_FIT], has_image);

	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_COLOR], has_image);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_SMOOTH], has_image);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_CHECKERBOARD], has_image);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_ENHANCE], has_image);

	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_SAVE], has_image);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_PRINT], has_image);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_INFO], has_image);

	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_LEFT], has_image);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_MIRROR], has_image);
	gtk_widget_set_sensitive(g.toolbar[TOOLBAR_RIGHT], has_image);
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

static void
on_notify_view_scale(
	GObject *object, GParamSpec *param_spec, G_GNUC_UNUSED gpointer user_data)
{
	double scale = 0;
	g_object_get(object, g_param_spec_get_name(param_spec), &scale, NULL);

	gchar *scale_str = g_strdup_printf("%.0f%%", round(scale * 100));
	gtk_label_set_text(GTK_LABEL(g.toolbar[TOOLBAR_SCALE]), scale_str);
	g_free(scale_str);

	// FIXME: The label doesn't immediately assume its new width.
}

static void
on_notify_view_playing(
	GObject *object, GParamSpec *param_spec, G_GNUC_UNUSED gpointer user_data)
{
	gboolean b = FALSE;
	g_object_get(object, g_param_spec_get_name(param_spec), &b, NULL);
	const char *name = b
		? "media-playback-pause-symbolic"
		: "media-playback-start-symbolic";

	GtkButton *button = GTK_BUTTON(g.toolbar[TOOLBAR_PLAY_PAUSE]);
	GtkImage *image = GTK_IMAGE(gtk_button_get_image(button));
	gtk_image_set_from_icon_name(image, name, GTK_ICON_SIZE_BUTTON);
}

static void
on_notify_view_boolean(
	GObject *object, GParamSpec *param_spec, gpointer user_data)
{
	gboolean b = FALSE;
	g_object_get(object, g_param_spec_get_name(param_spec), &b, NULL);
	gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(user_data), b);
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

static void
on_toolbar_view_toggle(GtkToggleButton *button, const char *property)
{
	g_object_set(g.view, property, gtk_toggle_button_get_active(button), NULL);
}

static void
toolbar_toggler(int index, const char *property)
{
	g_signal_connect(g.toolbar[index], "toggled",
		G_CALLBACK(on_toolbar_view_toggle), (gpointer) property);
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

static void
on_toolbar_view_command(intptr_t command)
{
	fiv_view_command(FIV_VIEW(g.view), command);
}

static void
toolbar_command(int index, FivViewCommand command)
{
	g_signal_connect_swapped(g.toolbar[index], "clicked",
		G_CALLBACK(on_toolbar_view_command), (void *) (intptr_t) command);
}

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

static void
toolbar_connect(int index, GCallback callback)
{
	g_signal_connect_swapped(g.toolbar[index], "clicked", callback, NULL);
}

// TODO(p): The text and icons should be faded, unless the mouse cursor is
// on the toolbar. However, GtkEventBox is of no use, because either buttons
// steal our {enter,leave}-notify-events, or we steal all their input.
// Not even connecting to these signals on children works, insensitive buttons
// will not trigger anything.
// TODO(p): The toolbar should not be visible in fullscreen, or should show up
// only when the cursor reaches the top of the screen. Translucency sounds
// like a good mechanism here. Presumably, GtkOverlay could be used for this,
// but it faces the same problem as above--the input model sucks.
// TODO(p): Simply hide it in fullscreen and add a replacement context menu.
static GtkWidget *
make_view_toolbar(void)
{
#define XX(id, constructor) g.toolbar[TOOLBAR_ ## id] = constructor;
	TOOLBAR(XX)
#undef XX

	gtk_widget_set_margin_start(g.toolbar[TOOLBAR_SCALE], 5);
	gtk_widget_set_margin_end(g.toolbar[TOOLBAR_SCALE], 5);

	// So that the width doesn't jump around in the usual zoom range.
	// Ideally, we'd measure the widest digit and use width(NNN%).
	gtk_label_set_width_chars(GTK_LABEL(g.toolbar[TOOLBAR_SCALE]), 5);
	gtk_widget_set_halign(g.toolbar[TOOLBAR_SCALE], GTK_ALIGN_CENTER);

	// GtkStatusBar solves a problem we do not have here.
	GtkWidget *view_toolbar = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 0);
	gtk_widget_set_name(view_toolbar, "toolbar");
	GtkBox *box = GTK_BOX(view_toolbar);

	// Exploring different versions of awkward layouts.
	for (int i = 0; i <= TOOLBAR_S1; i++)
		gtk_box_pack_start(box, g.toolbar[i], FALSE, FALSE, 0);
	for (int i = TOOLBAR_COUNT; --i >= TOOLBAR_S7; )
		gtk_box_pack_end(box, g.toolbar[i], FALSE, FALSE, 0);

	GtkWidget *center = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 0);
	for (int i = TOOLBAR_S1; ++i < TOOLBAR_S7; )
		gtk_box_pack_start(GTK_BOX(center), g.toolbar[i], FALSE, FALSE, 0);
	gtk_box_set_center_widget(box, center);

	toolbar_connect(TOOLBAR_BROWSE,        G_CALLBACK(switch_to_browser));
	toolbar_connect(TOOLBAR_FILE_PREVIOUS, G_CALLBACK(on_previous));
	toolbar_connect(TOOLBAR_FILE_NEXT,     G_CALLBACK(on_next));
	toolbar_command(TOOLBAR_PAGE_FIRST,    FIV_VIEW_COMMAND_PAGE_FIRST);
	toolbar_command(TOOLBAR_PAGE_PREVIOUS, FIV_VIEW_COMMAND_PAGE_PREVIOUS);
	toolbar_command(TOOLBAR_PAGE_NEXT,     FIV_VIEW_COMMAND_PAGE_NEXT);
	toolbar_command(TOOLBAR_PAGE_LAST,     FIV_VIEW_COMMAND_PAGE_LAST);
	toolbar_command(TOOLBAR_SKIP_BACK,     FIV_VIEW_COMMAND_FRAME_FIRST);
	toolbar_command(TOOLBAR_SEEK_BACK,     FIV_VIEW_COMMAND_FRAME_PREVIOUS);
	toolbar_command(TOOLBAR_PLAY_PAUSE,    FIV_VIEW_COMMAND_TOGGLE_PLAYBACK);
	toolbar_command(TOOLBAR_SEEK_FORWARD,  FIV_VIEW_COMMAND_FRAME_NEXT);
	toolbar_command(TOOLBAR_PLUS,          FIV_VIEW_COMMAND_ZOOM_IN);
	toolbar_command(TOOLBAR_MINUS,         FIV_VIEW_COMMAND_ZOOM_OUT);
	toolbar_command(TOOLBAR_ONE,           FIV_VIEW_COMMAND_ZOOM_1);
	toolbar_toggler(TOOLBAR_FIT,           "scale-to-fit");
	toolbar_toggler(TOOLBAR_COLOR,         "enable-cms");
	toolbar_toggler(TOOLBAR_SMOOTH,        "filter");
	toolbar_toggler(TOOLBAR_CHECKERBOARD,  "checkerboard");
	toolbar_toggler(TOOLBAR_ENHANCE,       "enhance");
	toolbar_command(TOOLBAR_PRINT,         FIV_VIEW_COMMAND_PRINT);
	toolbar_command(TOOLBAR_SAVE,          FIV_VIEW_COMMAND_SAVE_PAGE);
	toolbar_command(TOOLBAR_INFO,          FIV_VIEW_COMMAND_INFO);
	toolbar_command(TOOLBAR_LEFT,          FIV_VIEW_COMMAND_ROTATE_LEFT);
	toolbar_command(TOOLBAR_MIRROR,        FIV_VIEW_COMMAND_MIRROR);
	toolbar_command(TOOLBAR_RIGHT,         FIV_VIEW_COMMAND_ROTATE_RIGHT);
	toolbar_connect(TOOLBAR_FULLSCREEN,    G_CALLBACK(toggle_fullscreen));

	g_signal_connect(g.view, "notify::scale",
		G_CALLBACK(on_notify_view_scale), NULL);
	g_signal_connect(g.view, "notify::playing",
		G_CALLBACK(on_notify_view_playing), NULL);
	g_signal_connect(g.view, "notify::scale-to-fit",
		G_CALLBACK(on_notify_view_boolean), g.toolbar[TOOLBAR_FIT]);
	g_signal_connect(g.view, "notify::enable-cms",
		G_CALLBACK(on_notify_view_boolean), g.toolbar[TOOLBAR_COLOR]);
	g_signal_connect(g.view, "notify::filter",
		G_CALLBACK(on_notify_view_boolean), g.toolbar[TOOLBAR_SMOOTH]);
	g_signal_connect(g.view, "notify::checkerboard",
		G_CALLBACK(on_notify_view_boolean), g.toolbar[TOOLBAR_CHECKERBOARD]);
	g_signal_connect(g.view, "notify::enhance",
		G_CALLBACK(on_notify_view_boolean), g.toolbar[TOOLBAR_ENHANCE]);

	g_object_notify(G_OBJECT(g.view), "scale");
	g_object_notify(G_OBJECT(g.view), "playing");
	g_object_notify(G_OBJECT(g.view), "scale-to-fit");
	g_object_notify(G_OBJECT(g.view), "enable-cms");
	g_object_notify(G_OBJECT(g.view), "filter");
	g_object_notify(G_OBJECT(g.view), "checkerboard");
	g_object_notify(G_OBJECT(g.view), "enhance");

#ifndef HAVE_LCMS2
	gtk_widget_set_no_show_all(g.toolbar[TOOLBAR_COLOR], TRUE);
#endif
#ifndef HAVE_JPEG_QS
	gtk_widget_set_no_show_all(g.toolbar[TOOLBAR_ENHANCE], TRUE);
#endif

	GCallback callback = G_CALLBACK(on_view_actions_changed);
	g_signal_connect(g.view, "notify::has-image", callback, NULL);
	g_signal_connect(g.view, "notify::can-animate", callback, NULL);
	g_signal_connect(g.view, "notify::has-previous-page", callback, NULL);
	g_signal_connect(g.view, "notify::has-next-page", callback, NULL);
	callback();
	return view_toolbar;
}

static GtkWidget *
make_browser_sidebar(FivIoModel *model)
{
	GtkWidget *sidebar = fiv_sidebar_new(model);
	g_signal_connect(sidebar, "open-location",
		G_CALLBACK(on_open_location), NULL);

	g.plus = gtk_button_new_from_icon_name("zoom-in-symbolic",
		GTK_ICON_SIZE_BUTTON);
	gtk_widget_set_tooltip_text(g.plus, "Larger thumbnails");
	g_signal_connect(g.plus, "clicked",
		G_CALLBACK(on_toolbar_zoom), (gpointer) +1);

	g.minus = gtk_button_new_from_icon_name("zoom-out-symbolic",
		GTK_ICON_SIZE_BUTTON);
	gtk_widget_set_tooltip_text(g.minus, "Smaller thumbnails");
	g_signal_connect(g.minus, "clicked",
		G_CALLBACK(on_toolbar_zoom), (gpointer) -1);

	GtkWidget *zoom_group = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 0);
	gtk_style_context_add_class(
		gtk_widget_get_style_context(zoom_group), GTK_STYLE_CLASS_LINKED);
	gtk_box_pack_start(GTK_BOX(zoom_group), g.plus, FALSE, FALSE, 0);
	gtk_box_pack_start(GTK_BOX(zoom_group), g.minus, FALSE, FALSE, 0);

	GtkWidget *funnel = gtk_toggle_button_new();
	gtk_container_add(GTK_CONTAINER(funnel),
		gtk_image_new_from_icon_name("funnel-symbolic", GTK_ICON_SIZE_BUTTON));
	gtk_widget_set_tooltip_text(funnel, "Hide unsupported files");
	g_signal_connect(funnel, "toggled",
		G_CALLBACK(on_filtering_toggled), NULL);

	GtkWidget *menu = gtk_menu_new();
	g.sort_field[0] = gtk_radio_menu_item_new_with_mnemonic(NULL, "By _Name");
	g.sort_field[1] = gtk_radio_menu_item_new_with_mnemonic(
		gtk_radio_menu_item_get_group(GTK_RADIO_MENU_ITEM(g.sort_field[0])),
		"By _Modification Time");
	for (int i = FIV_IO_MODEL_SORT_MIN; i <= FIV_IO_MODEL_SORT_MAX; i++) {
		g_signal_connect(g.sort_field[i], "activate",
			G_CALLBACK(on_sort_field), (void *) (intptr_t) i);
		gtk_menu_shell_append(GTK_MENU_SHELL(menu), g.sort_field[i]);
	}

	g.sort_direction[0] =
		gtk_radio_menu_item_new_with_mnemonic(NULL, "_Ascending");
	g.sort_direction[1] = gtk_radio_menu_item_new_with_mnemonic(
		gtk_radio_menu_item_get_group(GTK_RADIO_MENU_ITEM(g.sort_direction[0])),
		"_Descending");
	g_signal_connect(g.sort_direction[0], "activate",
		G_CALLBACK(on_sort_direction), (void *) 0);
	g_signal_connect(g.sort_direction[1], "activate",
		G_CALLBACK(on_sort_direction), (void *) 1);

	gtk_menu_shell_append(GTK_MENU_SHELL(menu), gtk_separator_menu_item_new());
	gtk_menu_shell_append(GTK_MENU_SHELL(menu), g.sort_direction[0]);
	gtk_menu_shell_append(GTK_MENU_SHELL(menu), g.sort_direction[1]);
	gtk_widget_show_all(menu);

	GtkWidget *sort = gtk_menu_button_new();
	gtk_widget_set_tooltip_text(sort, "Sort order");
	gtk_button_set_image(GTK_BUTTON(sort),
		gtk_image_new_from_icon_name(
			"view-sort-ascending-symbolic", GTK_ICON_SIZE_BUTTON));
	gtk_menu_button_set_popup(GTK_MENU_BUTTON(sort), menu);

	GtkWidget *model_group = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 0);
	gtk_style_context_add_class(
		gtk_widget_get_style_context(model_group), GTK_STYLE_CLASS_LINKED);
	gtk_box_pack_start(GTK_BOX(model_group), funnel, FALSE, FALSE, 0);
	gtk_box_pack_start(GTK_BOX(model_group), sort, FALSE, FALSE, 0);

	GtkBox *toolbar = fiv_sidebar_get_toolbar(FIV_SIDEBAR(sidebar));
	gtk_box_pack_start(toolbar, zoom_group, FALSE, FALSE, 0);
	gtk_box_pack_start(toolbar, model_group, FALSE, FALSE, 0);
	gtk_widget_set_halign(GTK_WIDGET(toolbar), GTK_ALIGN_CENTER);

	g_signal_connect(g.browser, "notify::thumbnail-size",
		G_CALLBACK(on_notify_thumbnail_size), NULL);
	g_signal_connect(model, "notify::filtering",
		G_CALLBACK(on_notify_filtering), funnel);
	g_signal_connect(model, "notify::sort-field",
		G_CALLBACK(on_notify_sort_field), NULL);
	g_signal_connect(model, "notify::sort-descending",
		G_CALLBACK(on_notify_sort_descending), NULL);
	on_toolbar_zoom(NULL, (gpointer) 0);
	gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(funnel), TRUE);
	// TODO(p): Invoke sort configuration notifications explicitly.
	return sidebar;
}

// This is incredibly broken https://stackoverflow.com/a/51054396/76313
// thus resolving the problem using overlaps.
// We're trying to be universal for light and dark themes both. It's hard.
static const char stylesheet[] = "@define-color fiv-tile @content_view_bg; \
	fiv-view, fiv-browser { background: @content_view_bg; } \
	placessidebar.fiv .toolbar { padding: 2px 6px; } \
	placessidebar.fiv box > separator { margin: 4px 0; } \
	#toolbar button { padding-left: 0; padding-right: 0; } \
	#toolbar > button:first-child { padding-left: 4px; } \
	#toolbar > button:last-child { padding-right: 4px; } \
	#toolbar separator { \
		background: mix(@insensitive_fg_color, \
			@insensitive_bg_color, 0.4); margin: 6px 8px; \
	} \
	fiv-browser { padding: 5px; } \
	fiv-browser.item { \
		color: mix(#000, @content_view_bg, 0.625); margin: 8px; \
		border: 2px solid #fff; \
	} \
	fiv-browser.item, fiv-view.checkerboard { \
		background: @theme_bg_color; background-image: \
			linear-gradient(45deg, @fiv-tile 26%, transparent 26%), \
			linear-gradient(-45deg, @fiv-tile 26%, transparent 26%), \
			linear-gradient(45deg, transparent 74%, @fiv-tile 74%), \
			linear-gradient(-45deg, transparent 74%, @fiv-tile 74%); \
		background-size: 40px 40px; \
		background-position: 0 0, 0 20px, 20px -20px, -20px 0px; \
	} \
	fiv-browser.item:backdrop { \
		color: mix(#000, @content_view_bg, 0.875); \
		border-color: mix(#fff, @content_view_bg, 0.5); \
	} \
	fiv-browser.item.symbolic { \
		border-color: transparent; color: shade(@theme_bg_color, 0.875); \
		background: @theme_bg_color; background-image: none; \
	} \
	.fiv-information label { padding: 0 4px; }";

int
main(int argc, char *argv[])
{
	gboolean show_version = FALSE, show_supported_media_types = FALSE,
		browse = FALSE;
	gchar **path_args = NULL, *thumbnail_size = NULL;
	const GOptionEntry options[] = {
		{G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_FILENAME_ARRAY, &path_args,
			NULL, "[FILE | DIRECTORY]"},
		{"list-supported-media-types", 0, G_OPTION_FLAG_IN_MAIN,
			G_OPTION_ARG_NONE, &show_supported_media_types,
			"Output supported media types and exit", NULL},
		{"browse", 0, G_OPTION_FLAG_IN_MAIN,
			G_OPTION_ARG_NONE, &browse,
			"Start in filesystem browsing mode", NULL},
		{"thumbnail", 0, G_OPTION_FLAG_IN_MAIN,
			G_OPTION_ARG_STRING, &thumbnail_size,
			"Generate thumbnails for an image, up to the given size", "SIZE"},
		{"version", 'V', G_OPTION_FLAG_IN_MAIN, G_OPTION_ARG_NONE,
			&show_version, "Output version information and exit", NULL},
		{},
	};

	GError *error = NULL;
	gboolean initialized = gtk_init_with_args(
		&argc, &argv, " - Image browser and viewer", options, NULL, &error);
	if (show_version) {
		printf(PROJECT_NAME " " PROJECT_VERSION "\n");
		return 0;
	}
	if (show_supported_media_types) {
		for (char **types = fiv_io_all_supported_media_types(); *types; )
			g_print("%s\n", *types++);
		return 0;
	}
	if (!initialized)
		exit_fatal("%s", error->message);

	// NOTE: Firefox and Eye of GNOME both interpret multiple arguments
	// in a special way. This is problematic, because one-element lists
	// are unrepresentable.
	// TODO(p): Require a command line switch, load a virtual folder.
	// We may want or need to create a custom GVfs.
	// TODO(p): Complain to the user if there's more than one argument.
	// Best show the help message, if we can figure that out.
	const gchar *path_arg = path_args ? path_args[0] : NULL;
	if (thumbnail_size) {
		if (!path_arg)
			exit_fatal("no path given");

		FivThumbnailSize size = 0;
		for (; size < FIV_THUMBNAIL_SIZE_COUNT; size++)
			if (!strcmp(fiv_thumbnail_sizes[size].thumbnail_spec_name,
					thumbnail_size))
				break;
		if (size >= FIV_THUMBNAIL_SIZE_COUNT)
			exit_fatal("unknown thumbnail size: %s", thumbnail_size);

		GFile *target = g_file_new_for_commandline_arg(path_arg);
		if (!fiv_thumbnail_produce(target, size, &error))
			exit_fatal("%s", error->message);
		g_object_unref(target);
		return 0;
	}

	g.model = g_object_new(FIV_TYPE_IO_MODEL, NULL);

	gtk_window_set_default_icon_name(PROJECT_NAME);
	gtk_icon_theme_add_resource_path(
		gtk_icon_theme_get_default(), "/org/gnome/design/IconLibrary/");

	GtkCssProvider *provider = gtk_css_provider_new();
	gtk_css_provider_load_from_data(
		provider, stylesheet, sizeof stylesheet - 1, NULL);
	gtk_style_context_add_provider_for_screen(gdk_screen_get_default(),
		GTK_STYLE_PROVIDER(provider), GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
	g_object_unref(provider);

	GtkWidget *view_scroller = gtk_scrolled_window_new(NULL, NULL);
	g.view = g_object_new(FIV_TYPE_VIEW, NULL);
	g_signal_connect(g.view, "key-press-event",
		G_CALLBACK(on_key_press_view), NULL);
	g_signal_connect(g.view, "button-press-event",
		G_CALLBACK(on_button_press_view), NULL);
	gtk_container_add(GTK_CONTAINER(view_scroller), g.view);

	// Need to put the toolbar at the top, because of the horizontal scrollbar.
	g.view_box = gtk_box_new(GTK_ORIENTATION_VERTICAL, 0);
	g.view_toolbar = make_view_toolbar();
	gtk_box_pack_start(GTK_BOX(g.view_box), g.view_toolbar, FALSE, FALSE, 0);
	gtk_box_pack_start(GTK_BOX(g.view_box),
		gtk_separator_new(GTK_ORIENTATION_VERTICAL), FALSE, FALSE, 0);
	gtk_box_pack_start(GTK_BOX(g.view_box), view_scroller, TRUE, TRUE, 0);

	g.browser_scroller = gtk_scrolled_window_new(NULL, NULL);
	g.browser = fiv_browser_new(g.model);
	gtk_widget_set_vexpand(g.browser, TRUE);
	gtk_widget_set_hexpand(g.browser, TRUE);
	g_signal_connect(g.browser, "item-activated",
		G_CALLBACK(on_item_activated), NULL);
	gtk_container_add(GTK_CONTAINER(g.browser_scroller), g.browser);

	// Christ, no, do not scroll all the way to the top on focus.
	GtkWidget *browser_port = gtk_bin_get_child(GTK_BIN(g.browser_scroller));
	gtk_container_set_focus_hadjustment(GTK_CONTAINER(browser_port), NULL);
	gtk_container_set_focus_vadjustment(GTK_CONTAINER(browser_port), NULL);

	// TODO(p): As with GtkFileChooserWidget, bind C-h to filtering,
	// and mayhaps forward the rest to the sidebar, somehow.
	g.browser_sidebar = make_browser_sidebar(g.model);

	g.browser_paned = gtk_paned_new(GTK_ORIENTATION_HORIZONTAL);
	gtk_paned_add1(GTK_PANED(g.browser_paned), g.browser_sidebar);
	gtk_paned_add2(GTK_PANED(g.browser_paned), g.browser_scroller);
	g_signal_connect(g.browser_paned, "button-press-event",
		G_CALLBACK(on_button_press_browser_paned), NULL);

	g.stack = gtk_stack_new();
	gtk_stack_set_transition_type(
		GTK_STACK(g.stack), GTK_STACK_TRANSITION_TYPE_NONE);
	gtk_container_add(GTK_CONTAINER(g.stack), g.view_box);
	gtk_container_add(GTK_CONTAINER(g.stack), g.browser_paned);

	// TODO(p): Can we not do it here separately?
	gtk_widget_show_all(g.view_box);
	gtk_widget_show_all(g.browser_paned);

	g.window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
	g_signal_connect(g.window, "destroy",
		G_CALLBACK(gtk_main_quit), NULL);
	g_signal_connect(g.window, "key-press-event",
		G_CALLBACK(on_key_press), NULL);
	g_signal_connect(g.window, "window-state-event",
		G_CALLBACK(on_window_state_event), NULL);
	gtk_container_add(GTK_CONTAINER(g.window), g.stack);

	// Try to get half of the screen vertically, in 4:3 aspect ratio.
	//
	// We need the GdkMonitor before the GtkWindow has a GdkWindow (i.e.,
	// before it is realized). Take the smallest dimensions, out of desperation.
	GdkDisplay *display = gtk_widget_get_display(g.window);
	int unit = G_MAXINT;
	for (int i = gdk_display_get_n_monitors(display); i--; ) {
		GdkRectangle geometry = {};
		gdk_monitor_get_geometry(
			gdk_display_get_monitor(display, i), &geometry);
		unit = MIN(unit, MIN(geometry.width, geometry.height) / 6);
	}

	// Ask for at least 800x600, to cover ridiculously heterogenous setups.
	unit = MAX(200, unit);
	gtk_window_set_default_size(GTK_WINDOW(g.window), 4 * unit, 3 * unit);

	// XXX: The widget wants to read the display's profile. The realize is ugly.
	gtk_widget_realize(g.view);

	g.files = g_ptr_array_new_full(0, g_free);
	if (path_arg) {
		GFile *file = g_file_new_for_commandline_arg(path_arg);
		open_any_file(file, browse);
		g_object_unref(file);
	}
	if (!g.directory) {
		GFile *file = g_file_new_for_path(".");
		open_any_file(file, FALSE);
		g_object_unref(file);
	}

	gtk_widget_show_all(g.window);
	gtk_main();
	return 0;
}